Bridged phthalocyanine- and napththalocyanine-metal complex catalysts for oxidation reactions

ABSTRACT

Various embodiments disclosed relate to bridged phthalocyanine- and napththalocyanine-metal complex catalysts and methods using the same for oxidation reactions. In various embodiments, the present invention provides a method of oxidation including contacting an oxidizable starting material including an alkene with a catalyst and an oxidant, to provide an oxidized product.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of priority to U.S. ProvisionalPatent Application Ser. No. 63/220,282 filed Jul. 8, 2021, thedisclosure of which is incorporated herein in its entirety by reference.

BACKGROUND

Oxidation reactions are extremely common and useful, such as oxidationsof alcohols to ketones. However, most oxidation catalysts requireaddition of organic solvent, and require expensive and environmentallyharmful heavy or precious metals, and environmentally harmful oxidants.

SUMMARY OF THE INVENTION

In various embodiments, the present invention provides a method ofoxidation. The method includes contacting an oxidizable startingmaterial including an alkene with a catalyst and an oxidant, to providean oxidized product. The catalyst has the structure:

The variable M is a metal. Axial ligand L is a solvent molecule. At eachoccurrence, R^(A) and R^(B) are independently chosen from —H, halide, anorganic group, and a hydrophilic group, or R^(A) and R^(B) together forma fused aromatic ring with the ring upon which R^(A) and R^(B) aresubstituted, R^(A) and R⁸ together having the structure:

At each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ are each independentlychosen from —H, halide, an organic group, and a hydrophilic group.

In various embodiments, the catalyst had the structure:

Axial ligand is H₂O. The purified catalyst is about 95 wt % pure toabout 100 wt % pure.

In various embodiments, the catalyst has the structure:

The variable L is H₂O.

Various embodiments of the method of purifying the catalyst, thepurified catalyst, the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalyst,derivatives thereof, and methods of using the catalysts and derivatives,can have certain advantages over other purification methods, catalysts,and methods of using the same, at least some of which are unexpected.For example, in some embodiments, the purified catalyst, such as apurified catalyst provided by the method of catalyst purification, canhave different properties than less pure forms of the purified catalyst,such as providing catalysis of different types of reactions or providingdifferent rates of catalysis, or such as having different solubility invarious solvents. In various embodiments, the purified catalyst can havedifferent solubilities in various solvents, as compared to less pureforms of the purified catalyst, providing the ability to use thepurified catalyst in reactions wherein less pure forms of the catalystwould be less effective or ineffective. In various embodiments, thepurified catalyst can have greater solubility in non-aromatic alcohols,allowing for the use of the catalyst in a solvent-free oxidation ofnon-aromatic alcohols, wherein a less pure form of the purified catalystis less effective or ineffective for solvent-free oxidation ofnon-aromatic alcohols.

In various embodiments, the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalyst canprovide different properties than other catalysts, such as catalysis ofdifferent types of reactions or different rates of catalysis, or such ashaving different solubilities in various solvents. In variousembodiments, the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalyst canprovide a more effective scaffold for derivitization than othermaterials, such as compared toL(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)M catalysts. Forexample, in various embodiments, while the aromatic rings of anL(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)M catalyst are closerto nitrogen atoms and thus are relatively deactivated towardelectrophilic aromatic substitution, the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalystincludes aromatic rings that are further spaced from the nitrogen atomsof the bridged phthalocyanine structure, providing greater reactivitytoward electrophilic aromatic substitution.

In various embodiments, derivatives of the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalyst canprovide different properties than other catalysts, such as differentcatalytic activities than other catalysts, such as catalysis ofdifferent types of reactions or different rates of catalysis, or such ashaving different solubilities in various solvents. In variousembodiments, derivatives of the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalysthaving relatively polar groups substituted thereon, such as sulfonatedderivatives, can have enhanced water solubility compared tocorresponding catalysts not having such groups substituted thereon,broadening the types of materials that can be used with the catalyst. Invarious embodiments, derivatives of the(L)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)M catalysthaving relatively polar groups substituted thereon, such as sulfonatedderivatives, can be immobilized onto various substrates, such asion-exchange resins, providing a heterogeneous catalyst that can operatebetter than other catalysts in various solvents and that can easily beseparated from the reaction after use.

BRIEF DESCRIPTION OF THE FIGURES

The drawings illustrate generally, by way of example, but not by way oflimitation, various embodiments discussed in the present document.

FIGS. 1A-B illustrate molecular drawings generated from X-raydiffraction data for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III), inaccordance with various embodiments,

FIGS. 2A-B illustrate molecular drawings generated from X-raydiffraction data. for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III), inaccordance with various embodiments.

FIG. 3 illustrates a molecular drawing generated from X-ray diffractiondata for (H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III),in accordance with various embodiments.

FIGS. 4A-M illustrate X-ray data for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III) in Tables2-9, in accordance with various embodiments.

FIGS. 5A-D illustrate mass spectrometry data for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III), inaccordance with various embodiments.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to certain embodiments of thedisclosed subject matter, examples of which are illustrated in part inthe accompanying drawings. While the disclosed subject matter will bedescribed in conjunction with the enumerated claims, it will beunderstood that the exemplified subject matter is not intended to limitthe claims to the disclosed subject matter.

Throughout this document, values expressed in a range format should beinterpreted in a flexible manner to include not only the numericalvalues explicitly recited as the limits of the range, but also toinclude all the individual numerical values or sub-ranges encompassedwithin that range as if each numerical value and sub-range is explicitlyrecited. For example, a range of “about 0.1% to about 5%” or “about 0.1%to 5%” should be interpreted to include not just about 0.1% to about 5%,but also the individual values (e.g., 1%, 2%, 3%, and 4%) and thesub-ranges 0.1% to 0.5%, 1.1% to 2,2%, 3,3% to 4.4%) within theindicated range. The statement “about X to Y” has the same meaning as“about X to about Y,” unless indicated otherwise. Likewise, thestatement “about X, Y, or about Z” has the same meaning as “about X,about Y, or about Z,” unless indicated otherwise.

In this document, the terms “a,” “an,” or “the” are used to include oneor more than one unless the context clearly dictates otherwise. The term“or” is used to refer to a nonexclusive “or” unless otherwise indicated.The statement “at least one of A and B” has the same meaning as “A, B,or A and B.” In addition, it is to be understood that the phraseology orterminology employed herein, and not otherwise defined, is for thepurpose of description only and not of limitation. Any use of sectionheadings is intended to aid reading of the document and is not to beinterpreted as limiting; information that is relevant to a sectionheading may occur within or outside of that particular section.

In the methods described herein, the acts can be carried out in anyorder without departing from the principles of the invention, exceptwhen a temporal or operational sequence is explicitly recited.Furthermore, specified acts can be carried out concurrently unlessexplicit claim language recites that they be carried out separately. Forexample, a claimed act of doing X and a claimed act of doing Y can beconducted simultaneously within a single operation, and the resultingprocess will fall within the literal scope of the claimed process.

The term “about” as used herein can allow for a degree of variability ina value or range, for example, within 10%, within 5%, or within 1% of astated value or of a stated limit of a range, and includes the exactstated value or range.

The term “substantially” as used herein refers to a majority of, ormostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%,98%, 99%, 99. 99.9%, 99.99%, or at least about 99.999% or more, or 100%.

The term “organic group” as used herein refers to any carbon-containingfunctional group. For example, an oxygen-containing group such as analkoxy group, aryloxy group, aralkyloxy group, oxo(carbonyl) group, acarboxyl group including a carboxylic acid, carboxylate, and acarboxylate ester; a sulfur-containing group such as an alkyl and arylsulfide group; and other heteroatom-containing groups. Non-limitingexamples of organic groups include OR, OOR, OC(O)N(R)₂, CN, CF₃, OCF₃,R, C(O), methylenedioxy, ethylenedioxy, N(R)₂, SR, SOR, SO₂R, SO₂N(R)₂,SO₃R, C(O)R, C(O)C(O)R, C(O)CH₂C(O)R, C(S)R, C(O)OR, OC(O)R, C(O)N(R)₂,OC(O)N(R)₂, C(S)N(R)₂, (CH₂)_(0.2)N(R)C(O)R, (CH₂) ₀₋₂N(R)N(R)₂,N(R)N(R)C(O)R, N(R)N(R)C(O)OR, N(R)N(R)CON(R)₂, N(R)SO₂R, N(R)SO₂N(R)₂,N(R)C(O)OR, N(R)C(O)R, N(R)C(S)R, N(R)C(O)N(R)₂, N(R)C(S)N(R)₂,N(COR)COR, N(OR)R, C(═NH)N(R)₂, C(O)N(OR)R, C(═NOR)R, and substituted orunsubstituted (C₁-C₁₀₀)hydrocarbyl, wherein R can be hydrogen (inexamples that include other carbon atoms) or a carbon-based moiety, andwherein the carbon-based moiety can be substituted or unsubstituted.

The term “substituted” as used herein in conjunction with a molecule oran organic group as defined herein refers to the state in which one ormore hydrogen atoms contained therein are replaced by one or morenon-hydrogen atoms. The term “functional group” or “substituent” as usedherein refers to a group that can be or is substituted onto a moleculeor onto an organic group. Examples of substituents or functional groupsinclude, but are not limited to, a halogen (e.g., F, Cl, Br, and I); anoxygen atom in groups such as hydroxy groups, alkoxy groups, aryloxygroups, aralkyloxy groups, oxo(carbonyl) groups, carboxyl groupsincluding carboxylic acids, carboxylates, and carboxylate esters; asulfur atom in groups such as thiol groups, alkyl and aryl sulfidegroups, sulfoxide groups, sulfone groups, sulfonyl groups, andsulfonamide groups; a nitrogen atom in groups such as amines,hydroxyamines, nitriles, nitro groups, N-oxides, hydrazides, azides, andenmities; and other heteroatoms in various other groups. Non-limitingexamples of substituents that can be bonded to a substituted carbon (orother) atom include F, Cl, Br, I, OR, OOR, OC(O)N(R)₂, CN, NO, NO₂,ONO₂, azido, CF₃, OCF₃, R, O(oxo), S(thiono), C(O), methylenedioxy,ethylenedioxy, N(R)₂, SR, SOR, SO₂R, SO₂N(R)₂, SO₃R, C(O)R, C(O)C(O)R,C(O)CH₂C(O)R, C(S)R, C(O)OR, OC(O)R, C(O)N(R)₂, OC(O)N(R)₂, C(S)N(R)₂,(CH₂)_(0.2)N(R)C(O)R, (CH₂)₀₋₂N(R)N(R)₂, N(R)N(R)C(O)R, N(R)N(R)C(O)OR,N(R)N(R)CON(R)₂, N(R)SO₂R, N(R)SO₂N(R)₂, N(R)C(O)OR, N(R)C(O)R,N(R)C(S)R, N(R)C(O)N(R)₂, N(R)C(S)N(R)₂, N(COR)COR, N(OR)R, C(═NH)N(R)₂,C(O)N(OR)R, and C(═NOR)R, wherein R can be hydrogen or a carbon-basedmoiety; for example, R can be hydrogen, (C₁-C₁₀₀)hydrocarbyl, alkyl,acyl, cycloalkyl, aryl, aralkyl, heterocyclyl, heteroaryl, orheteroarylalkyl; or wherein two R groups bonded to a nitrogen atom or toadjacent nitrogen atoms can together with the nitrogen atom or atomsform a heterocyclyl.

The term “alkyl” as used herein refers to straight chain and branchedalkyl groups and cycloalkyl groups having from 1 to 40 carbon atoms, 1to about 2 carbon atoms, 1 to 12 carbons or, in some embodiments, from 1to 8 carbon atoms. Examples of straight chain alkyl groups include thosewith from 1 to 8 carbon atoms such as methyl, ethyl, n-propyl, n-butyl,n-pentyl, n-hexyl, n-heptyl, and n-octyl groups. Examples of branchedalkyl groups include, but are not limited to, isopropyl, iso-butyl,sec-butyl, t-butyl, neopentyl, isopentyl, and 2,2-dimethylpropyl groups.As used herein, the term “alkyl” encompasses n-alkyl, isoalkyl, andanteisoalkyl groups as well as other branched chain forms of alkyl.Representative substituted alkyl groups can be substituted one or moretimes with any of the groups listed herein, for example, amino, hydroxy,cyano, carboxy, nitro, thio, alkoxy, and halogen groups.

The term “alkenyl” as used herein refers to straight and branched chainand cyclic alkyl groups as defined herein, except that at least onedouble bond exists between two carbon atoms. Thus, alkenyl groups havefrom 2 to 40 carbon atoms, or 2 to about 20 carbon atoms, or 2 to 12carbon atoms or, in some embodiments, from 2 to 8 carbon atoms. Examplesinclude, but are not limited to vinyl, —CH═CH(CH₃), —CH═C(CH₃)₂,—C(CH₃)═CH₂, —C(CH₃)═CH(CH₃), —C(CH₂CH₃)═CH₂, cyclohexenyl,cyclopentenyl, cyclohexadienyl, butadienyl, pentadienyl, and hexadienylamong others.

The term “acyl” as used herein refers to a group containing a carbonylmoiety wherein the group is bonded via the carbonyl carbon atom. Thecarbonyl carbon atom is bonded to a hydrogen forming a “formyl” group oris bonded to another carbon atom, which can be part of an alkyl, aryl,aralkyl cycloalkyl, cycloalkylalkyl, heterocyclyl, heterocyclylalkyl,heteroatyl, heteroarylalkyl group or the like. An acyl group can include0 to about 12, 0 to about 20, or 0 to about 40 additional carbon atomsbonded to the carbonyl group. An acyl group can include double or triplebonds within the meaning herein. An acryloyl group is an example of anacyl group. An acyl group can also include heteroatoms within themeaning herein. A nicotinoyl group (pyridyl-3-carbonyl) is an example ofan acyl group within the meaning herein. Other examples include acetyl,benzoyl, phenylacetyl, pyridylacetyl, cinnamoyl, and acrylipyl groupsand the like, When the group containing the carbon atom that is bondedto the carbonyl carbon atom contains a halogen, the group is termed a“haloacyl” group. An example is a trifluoroacetyl group.

The term “cycloalkyl” as used herein refers to cyclic alkyl groups suchas, but not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, and cyclooctyl groups. In some embodiments, thecycloalkyl group can have 3 to about 8-12 ring members, whereas in otherembodiments the number of ring carbon atoms range from 3 to 4, 5, 6, or7. Cycloalkyl groups further include polycyclic cycloalkyl groups suchas, but not limited to, norbornyl, adamantyl, bornyl, camphenyl,isocamphenyl, and carenyl groups, and fused rings such as, but notlimited to, decalinyl, and the like. Cycloalkyl groups also includerings that are substituted with straight or branched chain alkyl groupsas defined herein. Representative substituted cycloalkyl groups can bemono-substituted or substituted more than once, such as, but not limitedto, 2,2-, 2,3-, 2,4- 2,5- or 2,6-disubstituted cyclohexyl groups ormono-, di- or tri-substituted norbornyl or cycloheptyl groups, which canbe substituted with, for example, amino, hydroxy, cyano, carboxy, nitro,thio, alkoxy, and halogen groups. The term “cycloalkenyl” alone or incombination denotes a cyclic alkenyl group.

The term “aryl” as used herein refers to cyclic aromatic hydrocarbongroups that do not contain heteroatoms in the ring. Thus aryl groupsinclude, but are not limited to, phenyl, azulenyl, heptalenyl, biphenyl,indacenyl, fluorenyl, phenanthrenyl, triphenylenyl, pyrenylnaphthacenyl, chrysenyl, biphenylenyl, anthracenyl, and naphthyl groups.In some embodiments, aryl groups contain about 6 to about 14 carbons inthe ring portions of the groups. Aryl groups can be unsubstituted orsubstituted, as defined herein. Representative substituted aryl groupscan be mono-substituted or substituted more than once, such as, but notlimited to, a phenyl group substituted at any one or more of 2-, 3-, 4-,5-, or 6-positions of the phenyl ring, or a naphthyl group substitutedat any one or more of 2- to 8-positions thereof.

The term “heterocyclyl” as used herein refers to aromatic andnon-aromatic ring compounds containing three or more ring members, ofwhich one or more is a heteroatom such as, but not limited to, N, O, andS.

The terms “halo,” “halogen,” or “halide” group, as used herein, bythemselves or as part of another substituent, mean, unless otherwisestated, a fluorine, chlorine, bromine, or iodine atom.

The term “haloalkyl” group, as used herein, includes mono-halo alkylgroups, poly-halo alkyl groups wherein all halo atoms can be the same ordifferent, and per-halo alkyl groups, wherein all hydrogen atoms arereplaced by halogen atoms, such as fluoro. Examples of haloalkyl includetrifluoromethyl, 1,1-dichloroethyl, 1,2-dichloroethyl,1,3-dibromo-3,3-difluoropropyl, perfluorobutyl, and the like.

The term “hydrocarbon” or “hydrocarbyl” as used herein refers to amolecule or functional group, respectively, that includes carbon andhydrogen atoms. The term can also refer to a molecule or functionalgroup that normally includes both carbon and hydrogen atoms but whereinall the hydrogen atoms are substituted with other functional groups.

As used herein, the term “hydrocarbyl” refers to a functional groupderived from a straight chain, branched, or cyclic hydrocarbon, and canbe alkyl, alkenyl, alkynyl, aryl, cycloalkyl, acyl, or any combinationthereof. Hydrocarbyl groups can be shown as (C_(a)-C_(b))hydrocarbyl,wherein a and b are integers and mean having any of a to b number ofcarbon atoms. For example, C₁-C₄)hydrocarbyl means the hydrocarbyl groupcan be methyl (C₁), ethyl (C₂), propyl (C₃), or butyl (C₄), and(C₀-C_(b))hydrocarbyl means in certain embodiments there is nohydrocarbyl group.

The term “solvent” as used herein refers to a liquid that can dissolve asolid, liquid, or gas. Non-limiting examples of solvents are silicones,organic compounds, water, alcohols, ionic liquids, and supercriticalfluids.

The term “room temperature” as used herein refers to a temperature ofabout 15° C. to 28° C.

The term “standard temperature and pressure” as used herein refers to20° C. and 101 kPa.

In various embodiments, salts having a positively charged counterion caninclude any suitable positively charged counterion. For example, thecounterion can be ammonium(NH₄ ⁺), or an alkali metal such as sodium(Na⁺), potassium (K⁺), or lithium (Li⁺). In some embodiments, thecounterion can have a positive charge greater than +1, which can in someembodiments complex to multiple ionized groups, such as Zn²⁺, Al³⁺, oralkaline earth metals such as Ca²⁺ or Mg²⁺.

In various embodiments, salts having a negatively charged counted on caninclude any suitable negatively charged counterion. For example, thecounterion can be a halide, such as fluoride, chloride, iodide, orbromide. In other examples, the counterion can be nitrate, hydrogensulfate, dihydrogen phosphate, bicarbonate, nitrite, perchlorate,iodate, chlorate, bromate, chlorite, hypochlorite, hypobromite, cyanide,amide, cyanate, hydroxide, permanganate. The counterion can be aconjugate base of any carboxylic acid, such as acetate or formate. Insome embodiments, a counterion can have a negative charge greater than−1, which can in some embodiments complex to multiple ionized groups,such as oxide, sulfide, nitride, arsenate, phosphate, arsenite, hydrogenphosphate, sulfate, thiosulfate, sulfite, carbonate, chromate,dichromate, peroxide, or oxalate.

U.S. Pat. No. 10,065,980 is hereby incorporated by reference in itsentirety.

Catalyst

In various embodiments, the present invention provides a catalyst. Thecatalyst can have the structure:

The variable M can be a metal. Herein metal atoms complexed with bridgedphthalocyanine -and napththalocyanine structures are drawn showing novalence state. However, the metal atoms have the appropriate valencestate that is consistent with the structure shown (e.g., II, III, IV,V). The variable M can be a Group VIII or IX transition metal. Thevariable M can be chosen from Co and Fe. The variable M can be Fe (e.g.,Fe(III)). The axial ligand L can be a solvent molecule. The axial ligandL can be chosen from MeOH and H₂O. The axial ligand L can be H₂O.

In various embodiments, the catalyst can be a purified catalyst. Thecatalyst can he purified by any suitable means. In some embodiments, thecatalyst is purified via an embodiment of the method of purifying acatalyst described herein. In some embodiments, the purified catalystcan exhibit certain properties not shown by the catalyst under impureconditions. For example, in some embodiments, the purified catalyst canhave exhibit different solubilities in various solvents, as compared tothe catalyst in impure conditions. The purified catalyst can have anysuitable purity, such as about 80 wt %—about 100 wt % pure, about 95 wt% to about 100 wt % pure, about 98 wt % to about 100 wt % pure, or about80 wt % pure or less, or equal to or greater than about 81 wt %, 82, 83,84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9,99.99, or about 99.999 wt % pure or more.

At each occurrence, R^(A) and R^(B) can be independently chosen fromhalide, an organic group, and a hydrophilic group, or R^(A) and R^(B)can together form a fused aromatic ring with the ring upon which R^(A)and R^(B) are substituted, R^(A) and R^(B) together having thestructure:

At each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ can be each independentlychosen from —H, halide, an organic group, and a hydrophilic group. Thehydrophilic group can be any suitable hydrophilic group. For example, ateach occurrence, the hydrophilic group can be chosen from —C(O)OH,—O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH, —OS(O)(O)OH, a saltthereof, a substituted or unsubstituted (C₁-C₅₀)hydrocarbyl esterthereof, and a combination thereof. The hydrophilic group can be—S(O)(O)OH.

In some embodiments, R^(A) and R^(B) can have the structure:

The variables R¹, R², R³, R⁴, R⁵, and R⁶ can be —H.

In some embodiments, R^(A) and R^(B) can have the structure:

The variables R¹ and R⁶ can be —H. At each occurrence, R², R³, R⁴, andR⁵ can be independently chosen from —H and a hydrophilic group. At onemore occurrences at least one of R², R³, R⁴, and R⁵ can be a hydrophilicgroup.

In some embodiments, R^(A) and R^(B) can have the structure:

The variables R¹ and R⁶ can be —H. At each occurrence, R², R³, R⁴, andR⁵ can be independently chosen from —H and —S(O)(O)OH. At one moreoccurrences at least one of R², R³, R⁴, and R⁵ can be —S(O)(O)OH.

In some embodiments, R¹, R^(A), R^(B), and R⁶ are —H. The catalyst canhave the structure:

Axial ligand L can be H₂O.

The catalyst can have the structure:

The variable M can be a metal. Herein metal atoms complexed with bridgedphthalocyanine- and napththalocyanine structures are drawn showing novalence state. However, the metal atoms have the appropriate valencestate that is consistent with the structure shown (e.g., II, III, IV, orV). The variable M can be a Group VIII or IX transition metal. Thevariable M can be chosen from Co and Fe. The variable M can be Fe (e.g.,Fe(III)). The axial ligand L can be a solvent molecule. The axial ligandL can be chosen from MeOH and H₂O. The axial ligand L can be H₂O.

At each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ can be independentlychosen from —H, halide, an organic group, and a hydrophilic group. Thehydrophilic group can be any suitable hydrophilic group. For example, ateach occurrence, the hydrophilic group can be chosen from —C(O)OH,—O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH, —OS(O)(O)OH, a saltthereof, a substituted or unsubstituted (C₁-C₅₀)hydrocarbyl esterthereof, and a combination thereof. The hydrophilic group can be—S(O)(O)OH.

In some embodiments, R¹ and R⁶ are —H, and at each occurrence, R², R³,R⁴, and R⁵ are independently chosen from —H and a hydrophilic group. Atone or more occurrences at least one of R², R³, R⁴, and R⁵ can be ahydrophilic group (e.g., at least one of R², R³, R⁴, or R⁵ in themolecule is a hydrophilic group).

In some embodiments, R¹ and R⁶ are —H, and at each occurrence, R², R³,R⁴, and R⁵ are independently chosen from —H and —S(O)(O)OH. At one ormore occurrences at least one of R², R³, R⁴, and R⁵ can be —S(O)(O)OH(e.g., at least one of R², R³, R⁴, or R⁵ in the molecule can be—S(O)(O)OH).

Various embodiments of the present invention provide a method ofoxidation including contacting an oxidizable starting material with thecatalyst and an oxidant, to provide an oxidized product. The oxidizablestarting material can be any suitable oxidizable starting material, suchas a substituted or unsubstituted (C₁-C₅₀)hydrocarbyl alcohol, such as2-pentanol, 1-pentanol, 2,4-dimethyl-3-pentanol, or isopropanol. Theoxidant can be any suitable oxidant, such as tort-butylhydroperoxide,hydrogen peroxide, and combinations thereof. In various embodiments, thecontacting to provide an oxidized product can be carried out undersolvent-containing or solvent-free conditions (e.g., wherein thereagents act as the solvent).

In various embodiments, the present invention provides a method offorming the catalyst. For example, the method can include combining asuitable M-containing reagent (e.g., Fe(OAc)₂) with a suitable material,such as 2,3-naphthalenedicarbonitrile, under conditions sufficient toproduce the catalyst.

In various embodiments, the present invention provides a method offorming a derivatized catalyst. The method can include adding ahydrophilic group to the catalyst, such as by electrophilic aromaticsubstitution. The method can include adding to the catalyst one or moreof —C(O)OH, —O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH, —OS(O)(O)OH,a salt thereof and a substituted or unsubstituted (C₁-C₅₀)hydrocarbylester thereof. The method can include adding to the catalyst —S(O)(O)OH,such as via treatment with sulfuric acid.

In various embodiments, the derivatized catalyst can have a greaterwater solubility than the un-derivatized catalyst, due to the added oneor more hydrophilic groups. Various embodiments of the present inventionprovide a method of oxidation including contacting a suitable oxidizablestarting material, a suitable oxidant, the derivatized catalyst, andwater.

Method of Oxidation

In various embodiments, the present invention provides a method ofoxidation. The method can include contacting an oxidizable startingmaterial with any embodiment of a catalyst described herein and anoxidant. The contacting of the oxidizable starting material, thecatalyst, and the oxidant, provides an oxidized product. In someembodiments, the catalyst is an embodiment of the catalyst describedherein. The catalyst can be unpurified or purified, such as having anysuitable purity, such as about 80 wt % to about 100 wt % pure, about 95wt % to about 100 wt % pure, about 98 wt % to about 100 wt % pure, orabout 80 wt % pure or less, or equal to or greater than about 81 wt %,82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99,99.9, 99.99, or about 99.999 wt % pure or more.

In various embodiments, the contacting to provide an oxidized product iscarried out under solvent-free conditions. Under such solvent-freeconditions, the liquid reagents (e.g., the oxidizable starting materialand the oxidized product) are suitable for dissolving the catalyst andthe oxidizing agent. For example, in various embodiments, the catalyst(e.g., the purified catalyst, or the unpurified catalyst) is soluble innon-aromatic alcohols, such that oxidation of such non-aromatic alcoholscan be carried out without the addition of any other solvents. In someembodiments, the catalyst remains undissolved and operates catalyticallyfrom a heterogeneous solution. The catalyst can be an unsupportedcatalyst, or the catalyst can comprise a solid support, such as carbon(e.g., activated charcoal, activated carbon, or graphene), or such asany suitable solid support (e.g., alumina or silica).

The oxidant can be any suitable oxidant. The oxidant can be chosen fromtert-butylhydroperoxide, hydrogen peroxide, and combinations thereof.The oxidant can be oxygen, such as oxygen provided by air. In someembodiments, oxygen from ambient air is the only oxidant provided.

The oxidizable starting material can be any suitable oxidizable startingmaterial. The oxidizable starting material can be a substituted orunsubstituted (C₁-C₅₀)hydrocarbyl alcohol. The oxidizable startingmaterial can be chosen from 2-pentanol, 1-pentanol, and2,4-dimethyl-3-pentanol. The oxidizable starting material can be anorganic compound including an alkene group. The alkene group can be aterminal alkene group. The oxidizable starting material can be styrene,and oxidized product can be styrene oxide, benzaldehyde, oligomerizationor polymerization products of styrene and/or of the oxidation productsthereof, or a combination thereof. The oxidizable starting material canbe cyclohexene, and the oxidized product can be cyclohexene oxide,2-cyclohexene-1-ol, 2-cyclohexene-1-one, 2,3-epoxy-1-cyclohexanol,2,3-epoxycyclohexanone, or a combination thereof.

During the contacting to provide the oxidized product, the catalyst canhave any suitable turnover number (e.g., the moles of product produceddivided by the moles of catalyst used). For example, the turnover numbercan be about 200 to about 10,000, about 300 to about 1,000, or about 200or less, or about 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750,800, 850, 900, 950, 1,000, 1,100, 1,200, 1,300, 1,400, 1,500, 1,600,1,800, 2,000, 2,500, 3,000, 4,000, 5,000, 6,000, 8,000, or about 10,000or more. During the contacting to provide the oxidized product, thecatalyst can have any suitable turnover frequency (e.g., turnover numberdivided by reaction time). For example, the turnover frequency can beabout 500 h⁻¹ to about 20,000 h⁻¹, about 1,000 h⁻¹ to about 4,000 h⁻¹,about 500 h⁻¹ or less, or about 600 h⁻¹, 800, 1,000, 1,100, 1,200,1,300, 1,400, 1,500, 1,600, 1,700, 1,800, 1,900, 2,000, 2,100, 2,200,2,300, 2,400, 2,500, 2,600, 2,700, 2,800, 2,900, 3,000, 3,500, 4,000,4,500, 5,000, 6,000, 7,000, 8,000, 9,000, 10,000, 15,000, or about 20,00h⁻¹ or more.

Method of Purifying a Catalyst

In various embodiments, the present invention provides a method ofpurifying a catalyst. The method can include contacting a catalystcomposition with acid. The catalyst composition includes a catalyst. Thecontacting provides an acidified catalyst composition with the catalystdissolved therein. The method can include precipitating the catalyst.The method can include removing the precipitated catalyst from solution,to provide a purified catalyst.

The acid can be any suitable acid. The acid can include one acid ormultiple acids. The acid can include an organic acid or a mineral acid.The acid can include sulfuric acid or hydrochloric add. The contactingof the catalyst composition with the add can be sufficient to provideany suitable pH in the acidified solution, such as a pH of about −3 toabout 6, about 0 to about 1, or about −3 or less, or about −2, −1, 0, 1,1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, or about 6 or more.

The catalyst can be fully dissolved in the acidified catalystcomposition. All materials in the acidified catalyst composition can befully dissolved. If undissolved materials remain in the acidifiedcatalyst composition, the undissolved materials can be removed prior tothe precipitation of the catalyst therefrom.

The precipitating of the catalyst from the acidified catalystcomposition can include at least partially neutralizing the acidifiedcomposition. The at least partially neutralizing includes bringing theacidified composition to any suitable pH, such as a pH of about 0.5 toabout 6, about 1 to about 4. or about 0.5 or less, or about 1, 1.5, 2,2.5, 3, 3.5, 4, 5, or about 6 or more. The at least partiallyneutralizing can be carried out in any suitable fashion, such as bycontacting the acidified composition with a base. The base can be anyone or more suitable bases. In some examples, the base can include NaOHor KOH.

The precipitating can include diluting the acidified composition withwater. In some embodiments, the diluting can occur prior to the at leastpartial neutralization. In some embodiments, the diluting can occurafter the at least partial neutralization. The diluting can includediluting with any suitable quantity of water such that a convenientvolume of formed for removal of the formed precipitate, such as withabout 0.01 to about 100 times the volume of the acidified composition,about 2 to about 10 times, or about 0.01 times or less, or about 0.1, 1,2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50,60, 70, 80, 90, or about 100 time the volume of the acidifiedcomposition or more.

The removing of the precipitate from solution (e.g., from the acidifiedsolution, which can be at least partially neutralized and diluted) caninclude washing the precipitated catalyst with water to remove anyremaining parts of the acidified composition thereon.

The method can include recrystallizing the precipitated catalyst from asuitable medium, such as from one or more organic solvents. In someembodiments, the method includes recrystallizing the precipitatedcatalyst from an alcohol, such as methanol, ethanol, or isopropanol.

The purified catalyst can have any suitable purity, such as about 50 wt% pure to about 100 wt % pure, about 95 wt % pure to about 100 wt %pure, greater than 98 wt % pure, about 50 wt % pure or less, or equal toor greater than about 55 wt % pure, 60, 65, 70, 75, 80, 85, 86, 87, 88,89, 90, 91, 92, 93, 94, 95, 95.5, 96, 96.5, 97, 97.5, 98, 98.5, 99,99.2, 99.4, 99.6, 99.8, 99.9, 99.99, or about 99.999 wt % pure or more.

The catalyst can have the structure:

The variable M can be a metal. Herein metal atoms complexed with bridgedphthalocyanine- and napththalocyanine structures are drawn showing novalence state. However, the metal atoms have the appropriate valencestate that is consistent with the structure shown (e.g., II, III, IV,V). The variable M can be a Group VIII or IX transition metal. Thevariable M can be chosen from Co and Fe. The variable M can be Fe (e.g.,Fe(III)). The axial ligand L can be a solvent molecule. The axial ligandL can be chosen from CH₃CN, MeOH, and H₂O. The axial ligand L can beH₂O.

At each occurrence, R^(A) and R^(B) can be independently chosen from —H,halide, an organic group, and a hydrophilic group, or R^(A) and R^(B)can together form a fused aromatic ring with the ring upon which R^(A)and R^(B) are substituted, R^(A) and R^(B) together having thestructure:

At each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ can be each independentlychosen from —H, halide, an organic group, and a hydrophilic group. Thehydrophilic group can be any suitable hydrophilic group. For example, ateach occurrence, the hydrophilic group can be chosen from —C(O)OH,—O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH, OS(O)(O)OH, a saltthereof, a substituted or unsubstituted (C₁-C₅₀)hydrocarbyl esterthereof, and a combination thereof. The hydrophilic group can be—S(O)(O)OH.

In some embodiments, R^(A) and R^(B) can have the structure:

The variables R¹, R², R³, R⁴, R⁵, and R⁶ can be —H.

In some embodiments, R^(A) and R^(B) can have the structure:

The variables R¹ and R⁶ can be —H. At each occurrence, R², R³, R⁴, andR⁵ can be independently chosen from —H and a hydrophilic group. At onemore occurrences at least one of R², R³, R⁴, and R⁵ can be a hydrophilicgroup.

In some embodiments, R^(A) and R^(B) can have the structure:

The variables R¹ and R⁶ can be —. At each occurrence, R², R³, R⁴, and R⁵can be independently chosen from —H and —S(O)(O)OH. At one moreoccurrences at least one of R², R³, R⁴, and R⁵ can be —S(O)(O)OH.

In some embodiments, R¹, R^(A), R^(B), and R⁶ are —H. The catalyst canhave the structure:

wherein axial ligand L can be H₂O.

Any suitable proportion of the catalyst composition can be the catalyst.For example, about 0.001 wt % to about 99.999 wt % of the catalystcomposition can be the catalyst, or about 0.001 wt % or less, or equalto or less than about 0.01 wt %, 0.1, 1, 2, 3, 4, 5, 6, 8, 10, 15, 20,25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 86, 88, 90, 91, 92,93, 94, 95, 96, 97, 98, 99, 99.9, 99.99, or about 99.999 wt % can becatalyst.

The catalyst composition can further include a secondary catalyst havinga different structure than the catalyst. The secondary catalyst can havethe structure:

The variables M, L, R^(A), R^(B), R¹, R², R³, R⁴, R⁵, and R⁶ cancorrespond to any atom or group describes for the correspondingvariables in the catalyst, so long as the secondary catalyst and thecatalyst have different structure.

In various embodiment, the method is particularly valuable forseparating a catalyst from a secondary catalyst wherein the catalyst andsecondary catalyst have similar or the same structures with theexception of the identity of the axial ligand, L. For example, themethod can be particularly valuable for separating a catalyst having anaxial ligand L of H₂O from a secondary catalyst having an axial ligand Lof MeOH. Thus, for example, the secondary catalyst can have thestructure

Axial ligand L in the secondary catalyst is MeOH.

The catalyst composition can include any suitable materials in additionto the catalyst, so long as the method can be performed as describedherein. In various embodiments, the majority of the catalyst compositioncan be the catalyst and the secondary catalyst. For example, about 50 wt% to 100 wt % of the catalyst composition can be the catalyst and thesecondary catalyst, or about 50 wt % or less, or greater than or equalto about 55 wt %, 60, 65, 70, 75, 80, 85, 86, 88, 90, 91, 92, 93, 94,95, 96, 97, 98, 99, 99.9, 99.99, 99.999, or about 100 wt %. The purifiedcatalyst can be substantially free of the secondary catalyst (e.g., caninclude 0 wt %, or less than about 0.0001 wt %, 0.001. 0.01, 0.1. 1, 2,3, 4, 5, 10, 15, or less than about 20 wt %).

EXAMPLES

Various embodiments of the present invention can be better understood byreference to the following Examples which are offered by way ofillustration. The present invention is not limited to the Examples givenherein.

Part I (14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III) Example1.1. Synthesis of(H₂O/MeOH)(14,28-[1.3-diiminoisoindolinato]phthalocyaninato)Fe(III)(1)

Iron(II) acetate tetrahydrate (44.2 mg, 0.254 mmol), 1,2-dicyanobenzene(194.6 mg, 1.52 mmol) and 4.0 mL methanol were combined in a glass vial,which was then placed in a PTFE-lined stainless steel autoclave andheated for seven days at 130° C. Upon opening the autoclave, a darkbrown solution was observed, along with some dark red crystals, suitablefor X-ray crystallography, and apparently amorphous solids. The solutionwas allowed to evaporate and the residue was dissolved in a minimalamount of dichloromethane. This solution was loaded onto a silica gelflash column. A red-brown band remained strongly adsorbed at the top ofthe column as organic impurities were eluted with 100 mL of a 50%toluene: 50% dichloromethane mixture, followed by 1.0 L of 100% toluene,then 100 mL of a 50% toluene: 50% dichloromethane mixture, then 200 mLof 100% dichloromethane. A broad red-brown band then quickly desorbedand eluted with 100% methanol and was collected. Slow evaporation of thesolvent yielded dark red crystals of 1 (46.0 mg, 0.0558-0.0570 mmol,22.0-22.5%) based upon the starting iron reagent. Because 1 was obtainedwith varying proportions of methanol and water as axial ligand L, theyield is reported as a range between 22.0% (assuming L is 100% water,with three additional non-ligand molecules of methanol present in thecrystal lattice) and 22.5% (assuming L is 100% methanol, with twoadditional non-ligand molecules of methanol present in the crystallattice). The relationship between the identity of L and the number ofco-crystallized methanol molecules is inferred from crystallographicresults. The identity of this sample was confirmed by comparison of itsIR and UV-VIS spectra to those of an authentic sample from a similarreaction that was fully characterized via X-ray crystallography.Satisfactory elemental analysis of 1 could not be obtained due topartial solvent loss from the crystal lattice upon drying. IR v_(max)/cm⁻¹ 3413 br, 3057 w, 2820 w, 1623 m, 1557 s, 1521 s, 1472 s,1444 s, 1396 s, 1353 w, 1321 m, 1310 m, 1296 m, 1207 m, 1161 m, 1144 m,1123 s, 1097 m, 1079 m, 1027 s, 1007 m, 993 m, 964 w, 948 m, 923 m, 880w, 845 w, 803 w, 778 m, 753 m, 730 vs, 701 m, 684 w, 666 w, 651 w, 637 wand 625 w. These data match with those obtained from an authentic sampleof 1 characterized by X-ray crystallography. The catalyst 1 was notsoluble in water. The catalyst 1 had poor solubility in non-aromaticalcohols to nearly zero solubility).

wherein L is H₂O or MeOH

Alternatively, up to a 40% yield of pure material was obtained viacareful methanol washing of crystals taken directly from theun-chromatographed residue in the reaction vessel.

Example 1.2. Purification of(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III) (2)

The mixed catalyst 1 from Example 1.1 was provided via careful methanolwashing of crystals taken directly from the un-chromatographed residuein the reaction vessel. A mass of 45 mg of the resulting solid was thendissolved in concentrated sulfuric acid (3 mL) and stirred overnight atroom temperature. The solution was then diluted to 20 mL with water andthe pH was raised to ˜2.0 using NaOH. The resulting solid was thencollected by filtration and washed with copious water. Pure crystalswere obtained by triturating this solid with ethanol followed bycrystallization from the ethanol via slow evaporation, to give(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III) (2)

wherein L is H₂O

Molecular drawings generated from X-ray diffraction data for 2 areillustrated in FIGS. 1A-B. The molecular drawings are shown with 50%(FIG. 1A) and 60% (FIG. 1B) probability ellipsoids, with H atoms notinvolved in hydrogen bonding omitted for clarity. Methanol solvatemolecules are omitted from FIG. 1B. IR data (KBr) was as follows (cm⁻¹)3241 (br), 1628 (m), 1563 (s), 1519 (s), 1471 (s), 1441 (s), 1398 (m),1322 (w), 1296 (w), 1193 (w), 1101 (s), 1031 (m), 730 (s), 459 (s). Thecatalyst 2 was not soluble in water, but had excellent solubility in allalcohols, including non-aromatic alcohols, other than methanol.

Example 1.3. Use of(H₂O)(14.28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III) (2)

The catalyst 2 from Example 1.2 was used in various reactions. Theturnover number (TON) indicates the moles of product produced divided bythe moles of catalyst used. All reactions were carried out in 3.0 mL ofneat substrate in magnetically stirred round bottom flasks that wereloosely closed with rubber septa. Catalysts were dissolved in thesubstrate, followed by oxidant addition. At the conclusion of the givenreaction times, product mixtures were passed through a short plug ofsilica gel with diethyl ether to remove the catalyst. Reactions employedexcess tort-butylhydroperoxide (TBHP) oxidant, added as a 70% by weightsolution in water. Products were identified and quantified by GC-MSemploying naphthalene as an internal standard.

Example 1.3.1. Oxidation of 2-pentanol to 2-pentanone

In a 30 min. reaction at room temperature, TON=928, corresponding to acatalyst turnover frequency (TOF, =TON divided by reaction time) of 1856h⁻¹. A mass of 2.5 (3.1 μmol) of catalyst was employed in this reaction,shown in Scheme 1. The yield on the basis of TBHP oxidant was 33%,determined via gas chromatography-mass spectrometry (GC-MS).

Example 1.3.2. Oxidation of 1-pentanol to Pentanal

In a 15 min. reaction at room temperature TON=356, corresponding toTOF=1426 ⁻¹. A mass of 1.0 mg (1.2 μmol) of catalyst was employed inthis reaction, shown in Scheme 2. The yield on the basis of TBHP oxidantwas 5.6%, determined via (GC-MS).

Example 1.3.3. Oxidation of 2,4-dimethyl-3-pentanol to2,4-dimethyl-3-pentanone

In a 15 min. reaction, TON=750, corresponding to TOF=3000 h⁻¹. Thereaction temperature was 55° _(C.,) necessary to provide adequatemixing/miscibility of the oxidant and substrate. A mass of 1.5 mg (1.9μmol) of catalyst was employed in this reaction, shown in Scheme 3. Theyield on the basis of TBHP oxidant was 12%, determined via (GC-MS).

Example 1.3.4. Oxidation of Cyclohexanol to Cyclohexanone

In a 15 min. reaction at room temperature, TON=520, corresponding toTOF=1000 h⁻¹. A mass of 1.1 mg (1.4 μmol) of catalyst was employed inthis reaction, shown in Scheme 4. The yield on the basis of TBHP oxidantwas 8.2%, determined via (GC-MS).

Part II. (18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)Fe(III)Example 2.1. Synthesis of(H₂O)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)Fe(III) (3)

Fe(OAc)₂ (34.4 mg, 0.1978 mmol) and 2,3-naphthalenedicarbonitrile (212.8mg, 1.194 mol) were combined in a glass vial with 4.0 mL methanol. Thevial was then sealed in a Teflon-lined autoclave and heated for one weekat 130° C. Upon opening the autoclave, the vial was observed to containa dark crystalline solid((H₂O)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)Fe(III)(3)) and lightly colored powdery solid impurities and a paleyellow/orange supernatant liquid. Single crystals of the dark solidsuitable for X-ray study were obtained from such reactions, having onlywater as the axial ligand. Although only 5 equivalents of2,3-naphthalenedicarbonitrile are required to produce 3, it has beenfound that yields are higher when using 6 equivalents, possibly due toan oligomerization side-reaction of the 2,3-naphthalenedicarbonitrile.The reaction scheme is shown in Scheme 5.

Purification of the bulk product was accomplished by washing withmethanol and water, followed by stirring in glacial acetic acid,followed by further water washing. The resulting red crystalline solidwas taken up into dichloromethane and loaded onto a silica gel column,whereon it adsorbed very strongly to the top of the column. Copiousdichloromethane was eluted through the column to remove impurities (thiswas essentially a solid phase extraction). The desired compound was thenremoved from the column by elution of 50% acetone/50% dichloromethane asa dark red band. The product solution thus obtained was evaporated andrecrystallized from dichloromethane to produce a dark red solid. Removalof trace solvents under vacuum afforded a material with an IR spectrum(KBr pellet) matching that of an authentic sample that had beencharacterized via X-ray methods. The IR data was as follows (KBr, cm⁻¹):3055.7 (w), 1622.0 (s), 1561.0 (vs), 1522.0 (s), 1463.0 (vs), 1435.0(s), 1372,2 (m), 1336.2 (m), 1264.7 (w), 1216.5 (w), 1189.6 (m), 1133.0(m), 1097.7 (m), 1049.5 (w), 1020.0 (m), 997.8 (m), 968.0 (m), 894.6(s), 801.5 (w), 787.5 (w), 756.7 (s), 742.5 (s), 569.2 (s), 521.4 (w),504.6 (w), 473.1 (s). Molecular drawings generated from X-raydiffraction data for 3 are illustrated in FIGS. 2A-B. The moleculardrawings are shown with H atoms attached to carbon atoms omitted forclarity. Methanol solvate molecules are omitted from FIG. 2B.

wherein L is H₂O

Example 2.2. Sulfonated Derivative (4)

The (H₂O)(18,36-[1,3-diimino-benzo[f]isoindole]phthalocyaninato)Fe(III)(3) from Example 2.1 (85 mg) was treated with fuming sulfuric acid (3.0mL) at room temperature for 68 hours, then the solution was diluted withwater and neutralized with NaOH. The resulting solution was allowed toevaporate to dryness and then extracted with ethanol, producing areddish brown solution that was filtered to remove the presumed Na₂SO₄byproduct produced during the neutralization step. The filtrate wasallowed to evaporate, resulting in a reddish solid with excellent watersolubility that is believed to include the sodium salt of the sulfonatediron complex (4) along with sodium sulfate impurities.

Example 2.3. Oxidation of Isopropanol to Acetone

The sulfonated derivative 4 from Example 2.2 was combined withisopropanol and excess hydrogen peroxide in water (30 wt % H₂O₂ inwater), which formed acetone, identified via reverse phase high pressureliquid chromatography (HPLC). The reaction is shown in Scheme 6.

Example 2.4. Immobilization on Ion-Exchange Resin and Oxidation of2-pentanol to 2-pentanone

The sulfonated derivative 4 from Example 2.2. was immobilized on theanion exchange resin diethylaminoethanol (DEAE)-Sepharose® (abeaded-form of agarose extracted from seaweed). The immobilized catalystwas combined with 2-pentanol and TBHP, which formed 2-pentanone, asshown in Scheme 7.

Example 2.5 Characterization of Sulfonated Derivative 4

The sulfonated catalyst(s) 4, which are pentasulfonated derivatives ofscaffold complex 3, have been determined to possess the general formula[C₆₀H_((30-x))FeN₁₁O₁₅S₅]^(x−), where X represents both the number ofdeprotonated sulfonic acid groups (thus rendering these groups assulfonates) and the overall charge on the anionic sulfonate complex. Thecharge compensating cations are Na⁺. The characterization has been madeby high resolution electrospray ionization (ESI) mass spectrometry(negative ion mode) through comparison of calculated and observed m/zratios, where m is ion mass and z is absolute ion charge, and also bycomparison of observed and calculated isotopic distribution patterns. Inall cases, axial water ligands on 4 are lost during ionization. In somecases, observed peaks correspond to sodium ion adducts of thepentasulfonated complexes that form during the ionization process. Whilenot providing direct structural information, the mass spectra clearlyshow that the starting material has been sulfonated five times.Presumably, there exists one sulfonyl (or sulfonate) group on each outerring of each complex. Isomers may be present.

Specifically, the following are observed in spectra recorded on sampleME1141 (3279):

(1) A peak is observed at m/z=338.9896, corresponding to a tetraanion offormula [C₆₀H₂₆FeN₁₁S₅O₁₅]⁴⁻, which is the formula for thepentasulfonated complex, presumably with one sulfonate group on each ofthe five outermost aromatic rings, after loss of the axial water ligandduring ionization and with one of the sulfonate groups existing as a(protonated) sulfonic acid group. The calculated m/z for this tetraanionis 338.9897, within 0.3 ppm of the observed value. Observed andcalculated isotopic patterns around this peak match very well. We do notknow whether the protonated sulfonic acid group exists in the originalsolution, or rather if the protonation occurs during the ESI process ofa completely deprotonated pentasulfonated complex.

(2) A peak is observed at m/z=344.4850, corresponding to a sodium ionadduct of the pentasulfonated complex with each sulfonic acid groupdeprotonated and after loss of the axial water ligand,[C₆₀H₂₅FeN₁₁S₅O₁₅Na]⁴⁻. The calculated m/z for this adduct is 344.4852,within 0.6 ppm of the observed value. Observed and calculated isotopicpatterns around this peak match very well. Presumably, the sodium ionadduct formed during the ESI process, due to the highly charged natureof the completely deprotonated pentasulfonated complex and presence ofmany sodium ions in the analyte solution. By completely deprotonated, wemean that all of the five sulfonic acid groups have been deprotonated.

(3) A peak is observed at m/z=459.6495, corresponding to a sodium ionadduct of the pentasulfonated complex after the axial water ligand islost and where one of the sulfonate groups exists as a (protonated)sulfonic acid group to give [C₆₀H₂₆FeN₁₁NaS₅O₁₅]³⁻. The calculated m/zfor this trianion is 459.6493, within 0.4 ppm of the observed value.Observed and calculated isotopic patterns around this peak match verywell. We do not know whether the protonated sulfonic acid group existsin the original solution, or rather if the protonation occurs during theESI process of a completely deprotonated pentasulfonated complex.

(4) A peak is observed at m/z=466.9765, corresponding to a disodiumadduct of the pentasulfonated complex with each sulfonic acid groupdeprotonated and after loss of the axial water ligand,[C₆₀H₂₅FeN₁₁Na₂S₅O₁₅]³⁻. The calculated m/z for this trianionic adductis 466.9766, within 0.2 ppm of the observed value. Observed andcalculated isotopic patterns around this peak match very well.

Part III. Oxidation of Non-Benzylic Alcohols Catalyzed By a “Helmet”Phthalocyaninato Iron Complex in the Absence of Added Organic Solvent: aSeemingly Minor Structural Modification of a Known Catalyst VastlyExpands Versatility

The “helmet” metallophthalocyaninato iron(III) system is a veryeffective catalyst for the oxidation of unactivated primary andsecondary alcohols under solvent free conditions, as shown in Scheme 8.

An iron(III) complex bearing a bicyclic pentadentate14,28-[1,3-diiminoisoindolinato]phthalocyaninato (diiPc) ligand and anaxial water ligand is very effective as a catalyst in oxidationreactions of three secondary aliphatic alcohols (2-pentanol,2,4-dimethyl-3-pentanol and cyclohexanol), one primary aliphatic alcohol(1-pentanol), and one bifunctional allyl alcohol(5-hydroxymethylfurfural) with tert-butylhydroperoxide (TBHP) in theabsence of added organic solvent other than the substrates themselves.All reactions proceed with high turnover numbers (TON) and turnoverfrequency (TOF) relative to related catalytic systems. Selectivity forthe expected aldehyde and ketone products is excellent, with noobservable over-oxidation to carboxylic acids in the two cases whereacids could be expected as possible products. Surprisingly, the presenceof only water as the monodentate axial ligand in the catalyst providessolubility in non-aromatic substrates, in sharp contrast to observationsfor diiPc complexes of Fe(III) where the axial monodentate ligandcompleting the coordination sphere of iron is a mixture of methanol andwater strongly favouring methanol. The formulation of the catalystemployed in reactions described here has been conclusively establishedvia single crystal X-ray methods. The catalysis results presentedrepresent a significant extension and generalization of utility for the(diiPc)Fe(III) system in solvent-free alcohol oxidations, because fourof the five substrates investigated can be described as unactivatedalcohols, contrasting with previous studies on this general catalyticsystem that involved only activated (benzylic) alcohols.

In the present Part is described the catalytic oxidation of fivenon-benzylic alcohol substrates with tert-butylhydroperoxide (TBHP),employing a diiPc complex of iron(III) that shows markedly increasedsolubility in non-aromatic alcohols relative to that observed for thespecific complexes used as catalysts in Parts I and II. The solubilityof the catalyst employed in the work described in the present paper issurprising following its characterization via X-ray crystallography,given the fact that it results from a seemingly minor modification ofthe complex. Because of this enhanced solubility, the helmetmetallophthalocyaninato iron(III) system exhibits catalytic behaviorwith a much wider and more diverse range of substrates.

The oxidation of primary and secondary alcohols is a transformation thatremains of fundamental importance in organic synthesis. The observationof good catalytic activity for the diiPcFe(III) moiety in the oxidationof unactivated alcohols represents a significant step forward,furthering the potential of the diiPcFe(III) system as a truly greencatalyst. The TON and TOF values reported in the present Part comparefavorably with those observed for similar alcohol oxidation systems,especially given the solvent-free nature of the transformations.

Equipment and materials. All solvents (HPLC grade or higher) werepurchased from commercial sources and used without drying ordistillation. All reagents were obtained from commercial sources in thehighest available purity and used as received. The FT-IR spectrum wasrecorded on a Nicolet iS5 spectrometer using a KBr pellet. Products fromall oxidation reactions were analyzed via GC-MS using an Agilent 7890Agas chromatograph employing an Agilent HP-5ms column of dimensions 30m×0.25 mm and ultrahigh purity helium carrier gas, operating incombination with an Agilent 5975C mass spectrometer.

Example 3-1. Catalyst Preparation

The catalyst employed in the reactions described here was prepared via atwo step process. In the first step, 1,2-dicyanobenzene was allowed toreact with iron(II) acetate under solvothermal conditions in methanol(130° C., 7 days), yielding a dark crystalline solid that was washedwith methanol and dried. The structure of this material has beendetermined via single crystal X-ray methods to be(L)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III), or(L)(diiPc)Fe(III) 1, where L represents an axially coordinatedmonodentate ligand consisting of a mixture of methanol and water in anapproximately 4:1 ratio, as reported earlier. Following isolation andwashing of 1, the mixed axial ligand L was converted to 100% water bytreatment with sulphuric acid. In a typical preparation, mixture 1 wasstirred overnight in concentrated sulphuric acid resulting in a deep redsolution that was diluted in water and carefully treated with 6M NaOHuntil the pH is approximately 2 and a dark solid precipitated. Theconverted product was then isolated as a powdery black solid followingfiltration on a glass frit and drying. The formulation of the solid thusobtained has been established as (H₂O(diiPc)Fe(III) 2 vita comparison ofits IR spectral features to the known IR spectrum of 1, and by singlecrystal X-ray methods. The latter of these two techniques conclusivelyidentified the identity of the axial ligand in 2 as 100% water with nocompositional disorder. Single crystals of 2 were obtained byrecrystallization of the solid as originally obtained in powder formfrom absolute ethanol via slow evaporation of the solvent. A structuraldrawing of 2 is presented in FIG. 3 , Where thermal ellipsoids are drawnat the 50% probability level. Further details regarding the structuraldetermination for 2 and secondary (IR) characterization are presented aselectronic supplementary information. Suitable elemental analysis for 2cannot be obtained because of slow and incomplete solvent (ethanol) lossfrom the crystal lattice. Samples of 2 employed as catalysts in theoxidation reactions described below were obtained via filtration anddrying without recrystallization, in order to avoid the presence ofsolvent that becomes entrained in solid 2 upon nearly completeevaporation of ethanolic solutions during recrystallization.Significantly, it was observed that 2 dissolves readily in a widevariety of non-aromatic primary and secondary alcohols other thanmethanol, in contrast to 1 which shows minimal to zero solubility in anyalcohol lacking an aromatic group. FIG. 3 illustrates a moleculardrawing generated from X-ray diffraction data for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III) andco-crystallized ethanol molecules shown with 50% probability ellipsoids.All H atoms not involved in hydrogen bonding have been omitted for thesake of clarity.

Example 3-2. Oxidation Experiments

All oxidation reactions occurred in magnetically stirred round bottomflasks that were loosely capped with rubber septa under air. The primaryoxidant in all reactions was 70% Cert-butylhydroperoxide (TBHP) as anaqueous solution. Oxidations of 1-pentanol, 2-pentanol and cyclohexanolwere carried out at room temperature. In the oxidation of2,4-dimethyl-3-pentanol, the reaction mixture was heated to 63° C. inorder to increase miscibility of the substrate with the oxidantsolution. In the oxidation of 5-hydroxymethylfurfural, the reactionmixture was heated to 33° C. in order to melt the alcohol, which is asolid at room temperature. In all reactions, the catalyst was firstdissolved in the substrate alcohol, then the oxidant solution was addedin a single aliquat. Reaction times and substrate to oxidant ratios werevaried in order to maximize TON and TOF. A summary of the optimizedresults of these experiments is presented in Table 1. At the conclusionof oxidation reactions, product mixtures were passed through short plugsof silica gel with copious diethyl ether in order to remove the catalystfrom solution. Identification of products was accomplished by GC-MSthrough consideration of a combination of retention times as compared tothose observed for authentic samples and fragmentation patterns observedin the corresponding mass spectra. Products were quantified againstnaphthalene as an internal standard.

TABLE 1 TOF Entry Substrate Product Substrate:oxidant Conditions TON h⁻¹1

3.2:1 R.T., 15 min. 320 1300 2

1.9:1 R.T., 30 min. 1200 2300 3

4.9:1 63° C., 6 min. 520 5400 4

2.0:1 R.T., 30 min. 840 1700 5

1.2:1 33° C., 6 min. 440 4400 6

22.0:1 R.T., 30 min. 370 7300 7

22.9:1 R.T., 30 min. 580 1200 8

17.0:1 85° C., 30 min. 840 1700 9

13.0:1 75° C., 30 min. 700 1400

Example 3-3. Results and Discussion: Oxidation of Primary and SecondaryNon-Benzylic Alcohols

The material 2 was observed to function as an active catalyst for theoxidation of five non-benzylic alcohols in the absence of added organicsolvent with tert-butyl hydroperoxiede serving as the primary oxidant.This observation represents a significant extension of the generalversatility of the (diiPc)Fe(III) moiety as a catalyst for organicoxidations. The results of the oxidation experiments are summarized inTable 1 (entries 1-5). For the purpose of comparison, and to highlightthe versatility of the (diiPc)Fe(III) system in oxidation catalysis,some of the results of the catalytic oxidation of four benzylic alcoholsthat employed 1 are included to provide examples of reactions carriedout under conditions that parallel those employed in reactions reportedfor the first time here as closely as possible in terms of reactiontimes and the primary oxidant employed (TBHP). The alcohol substrateschosen were selected with intent to demonstrate the utility of thediiPcFe(III) system with a diverse array of substrates. Included areresults for the oxidations of secondary aliphatic alcohols (2-pentanol,2,4-dimethyl-3-pentanol, and cyclohexanol), a primary aliphatic alcohol(1-pentanol), and a bifunctional primary allylic alcohol,5-hydroxymethylfurfural. The last of these transformations (entry 5) isan important step in the production of value-added oxidized productsfrom a biomass-sourced alcohol.

The results presented in entries 1-5 of Table 1 derive from experimentsthat were designed to maximize TON and TOF together for each substrate,as both favourable catalyst durability and reaction speed were sought tobe demonstrated. In the optimization procedure reaction times andsubstrate were varied to oxidant ratios to provide maximal values forthese metrics. In all cases, reaction times longer than those indicatedin Table 1 resulted in greater TON values, but these enhancements cameat the expense of TOF and indicated a slowing of the oxidation reactionsover time. One possible reason for this observation is discussed brieflybelow. In a general sense, oxidations of secondary aliphatic alcohols toproduce ketones (entries 2, 3, and 4) proceeded with greater TON valuesthan either of the non-benzylic primary alcohols studied (entries 1 and5). The TON and TOF values reported for the secondary aliphatic alcoholsin two out of three cases were on the same order of magnitude as thosefor oxidation of two secondary benzylic alcohols (entries 7 and 9). Theexception occurred in the oxidation of 2-pentanol to produce2-pentanone, which proceeds with TON=1200, the highest value that wasobserved over a reaction period of thirty minutes. The fastest oxidationobserved was of 2,4dimethyl-3-pentanol (entry 3) for which TOF=5400 h⁻¹. While this rather impressive result may be due in part to the elevatedreaction temperature (63° C.), it does constitute performance that is interms of TOF alone superior to almost all of the homogeneous catalyticsystems that function without added organic solvent. The oxidation of4-hydroxymethylfurfural (entry 5) proceeded nearly as rapidly, producing440 turnovers in only six minutes, corresponding to TOF=4400. Nosignificant background reaction was observed for any of thetransformations in entries 1-5 when these reactions were attempted inthe absence of catalyst under otherwise analogous conditions.

Significantly, none of the primary alcohol oxidations resulted in theformation of any detectable amount of carboxylic acid. In the oxidationof 5-hydroxymethylfurfural no evidence was observed that either thepre-existing aldehyde functional group present in the substrate or thealdehyde group formed in the oxidation of the alcohol functional groupwere oxidized further to produce carboxylic acids, While reactions wereexamined in which hydrogen peroxide served as the primary oxidant fornon-benzylic substrates, the observed results were vastly inferior tothose presented in Table 1 in terms of all relevant metrics. This waspresumably due at least in part to poor miscibility of aqueous hydrogenperoxide solution with the alcohol substrates under investigation. It isinteresting to note that hydrogen peroxide was also found in mostrespects to give inferior performance to that observed for TBHP forbenzylic alcohol oxidation.

Example 3-4. Results and Discussion: Evaluation of the diiPc Moiety as aGeneral Alcohol Oxidation Catalyst

Results for oxidation reactions catalyzed by 2 were, in a general sense,comparable to those observed in reactions for benzylic alcoholscatalyzed by 1. Although observed TON values were nominally higher andturnover frequencies were significantly higher for the more recentexperiments involving non-benzylic substrates, at least some of theapparent improvement in performance must be ascribed to higher ratios ofoxidant to substrate. The decision to employ the higher relative amountsof oxidant was borne in part from a desire to improve TON and TOF. Thisdecision was also taken in response to the observation that reactions ofnon-benzylic substrates proceeded very sluggishly and with low TONvalues when stoichiometries comparable to those previously employed wereapplied. Although the reason for this observation is not yet clear, itis quite reasonable to expect that higher oxidant concentrations werenecessary for oxidations of non-benzylic substrates in order to decreasethe likelihood that the axial position opposite the pentadentate diiPcligand on the catalyst will become occupied by an alcohol substratemolecule at the completion of a catalytic cycle. Occupation of thiscoordination site by the alcohol substrates themselves couldsignificantly decrease the solubility of the catalyst complex, given thevery low solubility of 1, which bears mostly methanol ligands at thisaxial site, in non-aromatic alcohols. Regardless of the specificmechanism by which 2 functions as a catalyst in alcohol oxidationreactions, higher oxidant concentrations can favour further cycling ofthe catalyst over effective de-activation of the catalyst due tomarkedly decreased solubility as the axial ligand position becomesoccupied by alcohol substrate.

The seemingly minor modification of 1 in which the monodentate axialligand L was converted from a methanol-water mixture heavily favouringmethanol to 100% water was obviously a vital factor in expanding theversatility of the diiPcfe(III) system. The solubility characteristicsof 2 were surprising and it is not clear why the presence of only wateras the axial monodentate ligand in 2 markedly increases solubility. Thisobservation could result from the fact that water ligands posses twohydrogen bond donors available for interaction with the (non-aromatic)alcohol substrates, as opposed to only one in the case of methanol (orother alcohols). Indeed, the solid state structure of 2 determined viasingle crystal X-ray methods employing a crystal grown from ethanolsolution includes two co-crystallized ethanol molecules that arehydrogen bonded to the axial water ligand, suggesting that similarinteractions are likely to occur in alcohol solutions. This hydrogenbonding in the solid state is conclusively identified by O—O distancesof 2.586(2) and 2.606(2) Å between the oxygen atom on water and theoxygen atoms on these ethanol molecules, and by H—O distances betweenthe hydrogen atoms of the water ligand and the ethanol oxygen atoms of1.75(1) and 1.78(1) Å. The solubility of 1 in benzylic alcohols ispresumably the result of interactions of the aromatic rings in the metalcomplex with those in the substrates.

In most of these catalytic systems for solvent free oxidation ofalcohols reaction times are undesirably long, which imply much lowerdegrees of rate enhancement than are evidenced by the turnoverfrequencies observed for the diiPcFe(III) moiety. Overall, thediiPcFe(III) system holds a significant advantage over many othercatalytic systems that function in the absence added organic solvent inthat diiPc complexes are very easily and inexpensively prepared.Further, in cases where primary alcohols are oxidized to aldehydes(entries 1, 5, 6 and 8 in Table 1) no evidence of over-oxidation tocarboxylic acid is observed, demonstrating excellent chemoselectivityfor (diiPc)Fe(III) in general.

The helmet phthalocyaninato iron(III) system, (diiPc)Fe(III),outperforms most other known homogeneous catalysts of a similar naturein terms of TON and TOF. The applicability of this system in oxidationreactions is now generalized to include both primary and secondaryaliphatic alcohols and one bifunctional allylic alcohol. Excellentselectivity is observed in all cases. Continuing improvements in thispromising system may be achieved by synthetic modifications on the diiPcligand that impart further enhancements to catalyst solubility insubstrates or water solubility, and/or superior stability in substratealcohols

Example 3-5. X-Ray Analysis

Single crystal X-ray analysis of 2-experimental: data collection: A redcrystal with approximate dimensions 0.08×0.08×0.08 mm³ was selectedunder oil under ambient conditions and attached to the tip of a MiTeGenMicroMount©. The crystal was mounted in a stream of cold nitrogen at100(1) K and centered in the X-ray beam by using a video camera. Crystalevaluation and data collection were performed on a Bruker Quazar SMARTAPEXII diffractometer with Mo K_(α) (λ=0.71073 Å) radiation and thediffractometer to crystal distance of 4.96 cm. Initial cell constantswere obtained from three series of ω scans at different starting angles.Each series consisted of 12 frames collected at intervals of 0.5° in a6° range about ω with the exposure time of 5 seconds per frame. Thereflections were successfully indexed by an automated indexing routinebuilt in the APEXII program suite. The final cell constants werecalculated from a set of 9955 strong reflections from the actual datacollection.

Data were collected by using the full sphere data collection routine tosurvey the reciprocal space to the extent of a full sphere to aresolution of 0.70 Å. A total of 111776 data were harvested bycollecting 6 sets of frames with 0.5° scans in ω and φ with exposuretimes of 20 sec per frame. These highly redundant datasets werecorrected fur Lorentz and polarization effects. The absorptioncorrection was based on fitting a function to the empirical transmissionsurface as sampled by multiple equivalent measurements.

Single crystal X-ray analysis of 2-structure solution and refinement.The systematic absences in the diffraction data were uniquely consistentfor the space group P2₁/n that yielded chemically reasonable andcomputationally stable results of refinement. A successful solution bythe direct methods provided most non-hydrogen atoms from the E-map. Theremaining non-hydrogen atoms were located in an alternating series ofleast-squares cycles and difference Fourier maps. All non-hydrogen atomswere refined with anisotropic displacement coefficients. All hydrogenatoms not involved in hydrogen bonding were included in the structurefactor calculation at idealized positions and were allowed to ride onthe neighboring atoms with relative isotropic displacement coefficients.The O—H distances were refined with restraints, but the H atom positionswere allowed to refine. There are also three molecules of solvent EtOHper Fe complex in the lattice. The final least-squares refinement of 577parameters against 12032 data resulted in residuals R (based on F² forI≥2σ) and wR (based on F² for all data) of 0.0374 and 0.0969,respectively. The final difference Fourier map was featureless.

Summary—Crystal Data for C₄₆H₄₀FeN₁₁O₄ (M=866.74 g/mol): monoclinic,space group P2₁/n (no. 14), a=15.200(4) Å, b=13.875(4) Å, c=19.210(5) Å,β=104.532(11)°, V=3922(2) Å, Z=4, T=100.04 K, μ(MoKα)=0.448 mm⁻¹,Dcalc=1.468 g/cm³, 111776 reflections measured (3.068°≤2Θ≤61.142°),12032 unique (R_(int)=0.0541, R_(sigma)=0.0290) which were used in allcalculations. The final R₁ was 0.0374 (I>2σ(I)) and wR₂ was 0.0969 (alldata)

FIGS. 4A-M illustrate X-ray data for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III), shown inTables 2-9.

IR for 2 (KBr, cm⁻¹): 3421 (br), 1628.2 (m), 1563.6 (s), 1519.9 (s),1471 (s), 1441.5 (s), 1397.6 (m), 1322.2 (m), 1295.6 (w), 1193.5 (m),1100 (w), 1031.6 (w), 730.3 (s), 458.5 (br).

Mass spectrometry data for 2. Sample was isolated and purified via flashcolumn and recrystallization from methylene chloride and methanol.Formula: C₆₀H₃₂FeN₁₁O (4-cocrystalized MeOH molecules also). Molecularweight, without co-crystalized solvent=978.81.

Example 3-6

Compound 2, which had already been characterized via single crystalX-ray diffraction methods and secondarily by IR spectroscopy, has nowbeen further characterized via electrospray ionization (ESI) massspectrometry. FIGS. 5A-D illustrate mass spectrometry data for(H₂O)(14,28-[1,3-diiminoisoindolinato]phthalocyaninato)Fe(III), 2.Specifically, the mass spectrum obtained showed a peak at mass 961.2108,corresponding to the compound claimed after loss of the water ligand Land acquisition of a single proton during the course of ionization,having formula [C₆₀H₃₀N₁₁FeH]⁺ for which the calculated mass is961.2109. This agreement between observed and calculated masses iswithin 0.1 ppm. The loss of a water ligand from the claimed compound andacquisition of a proton during ionization is completely reasonable froma chemical standpoint. This observation constitutes definitivecharacterization of the claimed compound secondary to the alreadypresented X-ray data.

Example 3-7. Oxidation of Styrene to Benzaldehyde

Catalyst 2 as prepared in Example 3-1 was combined with neat styrene,using air as the only oxidant. The styrene was partially oxidized tobenzaldehyde as well as partially epoxidized to 2-phenyloxirane. Styreneoligomerization/polymerization also appeared to occur.

Example 3-8. Oxidation of Cyclohexene

Catalyst 2 as prepared in Example 3-1 was combined with neatcyclohexene, using air as the only oxidant. The cyclohexene waspartially oxidized to form cyclohexene oxide, 2-cyclohexene-1-ol, and2-cyclohexene-1-one. The oxidation proceeded more rapidly at elevatedtemperatures.

The procedure was repeated using dichloromethane as solvent. The samereaction proceeded to occur to produce the same products. The reactionappeared to be somewhat more facile than in neat cyclohexene.

The procedure was repeated by initially stirring catalyst 2 inacetonitrile to exchange the original axial ligand for CH₃CN. Then, avolume of dichloromethane was added approximately equal to the volume ofacetonitrile used. Finally, a cyclohexane substrate was added. Thisresulted in improved yields of cyclohexene oxide, 2-cyclohexene-1-ol,and 2-cyclohexene-1-one, as compared to the use of the water-ligandcatalyst. Further, the additional products 2,3-epoxy-1-cyclohexanol and2,3-epoxycyclohexanone were observed, which indicate likely epoxidationof 2-cyclohexen-1-ol and 2-cyclohexen-1-one after these are formed asinitial products.

The procedure was repeated using catalyst 2 supported on activatedcharcoal in an heterogeneous system with neat cyclohexene. The reactionproduced cyclohexene oxide, 2-cyclohexene-1-ol, and 2-cyclohexene-1-one.

The terms and expressions that have been employed are used as terms ofdescription and not of limitation, and there is no intention in the useof such terms and expressions of excluding any equivalents of thefeatures shown and described or portions thereof, but it is recognizedthat various modifications are possible within the scope of theembodiments of the present invention. Thus, it should be understood thatalthough the present invention has been specifically disclosed byspecific embodiments and optional features, modification and variationof the concepts herein disclosed may be resorted to by those of ordinaryskill in the art, and that such modifications and variations areconsidered to be within the scope of embodiments of the presentinvention.

Additional Embodiments

The following exemplary embodiments are provided, the numbering of whichis not to be construed as designating levels of importance:

Embodiment 1 provides a method of purifying a catalyst, the methodcomprising:

contacting a catalyst composition with acid, the catalyst compositioncomprising a catalyst, to provide an acidified catalyst composition withthe catalyst dissolved therein, the catalyst having the structure:

wherein

-   -   M is a metal,    -   axial ligand L is a solvent molecule,    -   at each occurrence, R^(A) and R^(B) are independently chosen        from —H, halide, an organic group, and a hydrophilic group, or        R^(A) and R^(B) together form a fused aromatic ring with the        ring upon which R^(A) and R^(B) are substituted, R^(A) and R^(B)        together having the structure:

and

-   -   at each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ are each        independently chosen from —H, halide, an organic group, and a        hydrophilic group;        precipitating the catalyst; and        removing the precipitated catalyst from solution, to provide a        purified catalyst.

Embodiment 2 provides the method of Embodiment 1, wherein the acid isone or more mineral acids.

Embodiment 3 provides the method of any one of Embodiments 1-2, whereinthe acid is sulfuric acid.

Embodiment 4 provides the method of any one of Embodiments 1-3, whereinthe acidified catalyst composition has a pH of about -3 to about 6.

Embodiment 5 provides the method of any one of Embodiments 1-4, whereinthe acidified catalyst composition has a pH of about 0 to about 1.

Embodiment 6 provides the method of any one of Embodiments 1-5, whereinthe catalyst is fully dissolved in the acidified catalyst composition.

Embodiment 7 provides the method of any one of Embodiments 1-6, whereinall materials in the acidified catalyst composition are fully dissolved.

Embodiment 8 provides the method of any one of Embodiments 1-7, furthercomprising separating any undissolved materials in the acidifiedcatalyst composition from the acidified catalyst composition prior tothe precipitating.

Embodiment 9 provides the method of any one of Embodiments 1-8, whereinthe precipitating comprises at least partially neutralizing theacidified composition.

Embodiment 10 provides the method of Embodiment 9, wherein the at leastpartially neutralizing comprises bringing the acidified composition to aof about 0.5 to about 6.

Embodiment 11 provides the method of any one of Embodiments 9-10,wherein the at least partially neutralizing comprises bringing theacidified composition to a pH of about 1 to about 4.

Embodiment 12 provides the method of any one of Embodiments 9-11,wherein the at least partially neutralizing comprises contacting theacidified composition with a base.

Embodiment 13 provides the method of any one of Embodiments 9-12,wherein the at least partially neutralizing comprises contacting theacidified composition with at least one of NaOH and KOH.

Embodiment 14 provides the method of any one of Embodiments 1-13,wherein precipitating comprises diluting the acidified composition withwater.

Embodiment 15 provides the method of Embodiment 14, wherein the dilutingcomprises diluting with water that has a volume of about 0.01 to about100 times the volume of the acidified composition.

Embodiment 16 provides the method of any one of Embodiments 14-15,wherein the diluting comprises diluting with water that has a volume ofabout 2 to about 10 times the volume of the acidified composition.

Embodiment 17 provides the method of any one of Embodiments 1-16,wherein the removing comprises washing the precipitated catalyst withwater.

Embodiment 18 provides the method of any one of Embodiments 1-17,further comprising recrystallizing the precipitated catalyst, to providethe purified catalyst.

Embodiment 19 provides the method of any one of Embodiments 1-18,further comprising recrystallizing the precipitated catalyst fromethanol, to provide the purified catalyst.

Embodiment 20 provides the method of any one of Embodiments 1-19,wherein the purified catalyst is about 95 wt % pure to about 100 wt %pure.

Embodiment 21 provides the method of any one of Embodiments 1-20,wherein the purified catalyst is greater than 98 wt % pure.

Embodiment 22 provides the method of any one of Embodiments 1-21,wherein M is a Group VIII or IX transition metal.

Embodiment 23 provides the method of any one of Embodiments 1-22,wherein M is chosen from Co and

Embodiment 24 provides the method of any one of Embodiments 1-23,wherein M is Fe.

Embodiment 25 provides the method of any one of Embodiments 1-24,wherein axial ligand L is chosen from CH₃CN, MeOH, and H₂O.

Embodiment 26 provides the method of any one of Embodiments 1-25,wherein axial ligand L is H₂O.

Embodiment 27 provides the method of any one of Embodiments 1-26,wherein at each occurrence, the hydrophilic group is chosen from—C(O)OH, —O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH, —OS(O)(O)OH, asalt thereof, a substituted or unsubstituted (C₁-C₅₀)hydrocarbyl esterthereof, and a combination thereof.

Embodiment 28 provides the method of any one of Embodiments 1-27,wherein at each occurrence, the hydrophilic group is —S(O)(O)OH.

Embodiment 29 provides the method of any one of Embodiments 1-28,wherein R^(A) and R^(B) have the structure:

and

-   -   wherein R¹, R², R³, R⁴, R⁵ and R⁶ are —H.

Embodiment 30 provides the method of any one of Embodiments 1-29,wherein R^(A) and R^(B) have the structure:

wherein

-   -   R¹ and R⁶ are —H, and    -   at each occurrence, R², R³, and R⁵ are independently chosen from        —H and a hydrophilic group.

Embodiment 31 provides the method of Embodiment 30, wherein at one moreoccurrences at least one of R², R³, R⁴, and R⁵ is a hydrophilic group.

Embodiment 32 provides the method of any one of Embodiments 1-31,wherein R^(A) and R^(B) have the structure:

wherein

-   -   R¹ and R⁶ are —H, and    -   at each occurrence, R², R³, R⁴, and R⁵ are independently chosen        from —H and —S(O)(O)OH.

Embodiment 33 provides the method of Embodiment 32, wherein at one moreoccurrences at least one of R², R³, R⁴, and R⁵ is —S(O)(O)OH.

Embodiment 34 provides the method of Embodiment 1-33, wherein R¹, R^(A),R^(B), and R⁶ are —H.

Embodiment 35 provides the method of any one of Embodiments 1-34,wherein the catalyst has the structure:

wherein axial ligand L is H₂O.

Embodiment 36 provides the method of any one of Embodiments 1-35,wherein about 0.001 wt % to about 99.999 wt % of the catalystcomposition is the catalyst.

Embodiment 37 provides the method of any one of Embodiments 1-36,wherein the catalyst composition further comprises a secondary catalyst,wherein the secondary catalyst has a different structure than thecatalyst, wherein the secondary catalyst has the structure:

wherein

-   -   M is a metal,    -   axial ligand L is a solvent molecule,    -   at each occurrence, R^(A) and R^(B) are independently chosen        from —H, halide, an organic group, and a hydrophilic group, or        R^(A) and R^(B) together form a fused aromatic ring with the        ring upon which R^(A) and R^(B) are substituted, R^(A) and R^(B)        together having the structure:

-   -   at each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ are each        independently chosen from —H, halide, an organic group, and a        hydrophilic group.

Embodiment 38 provides the method of Embodiment 37, wherein thesecondary catalyst has the structure:

wherein axial ligand L is MeOH or CH₃CN.

Embodiment 39 provides the method of any one of Embodiments 37-38,wherein 50 wt % to 100 wt % of the catalyst composition is the catalystand the secondary catalyst.

Embodiment 40 provides the method of any one of Embodiments 37-39,wherein 100 wt % of the catalyst composition is the catalyst and thesecondary catalyst.

Embodiment 41 provides the method of any one of Embodiments 37-40,wherein the purified catalyst is substantially free of the secondarycatalyst.

Embodiment 42 provides the purified catalyst of any one of Embodiments1-41.

Embodiment 43 provides a method of purifying a catalyst, the methodcomprising

contacting a catalyst composition with acid, the catalyst compositioncomprising a catalyst, to provide an acidified catalyst compositionhaving a pH of about 0 to about 1 with the catalyst dissolved therein,the catalyst having the structure:

-   -   wherein axial ligand L is H₂O,    -   wherein the catalyst composition further comprises a secondary        catalyst having the structure:

-   -   wherein L is MeOH;    -   precipitating the catalyst, comprising bringing the pH of the        acidified composition to about 1 to about 4;    -   removing the precipitated catalyst from solution;    -   washing the precipitated catalyst with water; and    -   recrystallizing the precipitated catalyst, to provide a purified        catalyst.

Embodiment 44 provides a catalyst having the structure:

wherein

-   -   M is a metal,    -   axial ligand L is a solvent molecule,    -   at each occurrence, R^(A) and R^(B) are independently chosen        from —H, halide, an organic group, and a hydrophilic group, or        R^(A) and R^(B) together form a fused aromatic ring with the        ring upon which R^(A) and R^(B) are substituted, R^(A) and R^(B)        together having the structure:

and

-   -   at each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ are each        independently chosen from —H, halide, an organic group, and a        hydrophilic group.

Embodiment 45 provides the method of Embodiment 44, wherein M is a GroupVIII or IX transition metal.

Embodiment 46 provides the catalyst of any one of Embodiments 44-45,wherein M is chosen from Co and Fe.

Embodiment 47 provides the catalyst of any one of Embodiments 44-46,wherein M is Fe.

Embodiment 48 provides the catalyst of any one of Embodiments 44-47,wherein axial ligand L is chosen from CH₃CN, MeOH, and H₂O.

Embodiment 49 provides the catalyst of any one of Embodiments 44-48,wherein axial ligand L is H₂O.

Embodiment 50 provides the catalyst of any one of Embodiments 44-49,wherein at each occurrence, the hydrophilic group is chosen from—C(O)OH, —O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH, —OS(O)(O)OH, asalt thereof, a substituted or unsubstituted (C₁-C₅₀)hydrocarbyl esterthereof, and a combination thereof.

Embodiment 51 provides the catalyst of any one of Embodiments 44-50,wherein at each occurrence, the hydrophilic group is —S(O)(O)OH.

Embodiment 52 provides the catalyst of any one of Embodiments 44-51,wherein R^(A) and R^(B) have the structure:

and

-   -   wherein R¹, R², R³, R⁴, R⁵, and R⁶ are —H.

Embodiment 53 provides the catalyst of any one of Embodiments 44-52,wherein R^(A) and R^(B) have the structure:

wherein

-   -   R¹ and R⁶ are —H, and    -   at each occurrence, R², R³, R⁴, and R⁵ are independently chosen        from —H and a hydrophilic group.

Embodiment 54 provides the catalyst of Embodiment 53, wherein at onemore occurrences at least one of R², R³, R⁴, and R⁵ is a hydrophilicgroup.

Embodiment 55 provides the catalyst of any one of Embodiments 44-54,wherein R^(A) and R^(B) have the structure:

wherein

-   -   R¹ and R⁶ are —H, and    -   at each occurrence, R², R³, R⁴, and R⁵ are independently chosen        from —H and —S(O)(O)OH.

Embodiment 56 provides the catalyst of Embodiment 55, wherein at onemore occurrences at least one of R², R³, R⁴, and R⁵ is —S(O)(O)OH.

Embodiment 57 provides the catalyst of any one of Embodiments 44-56,wherein R¹, R^(A), R^(B), and R⁶ are —H.

Embodiment 58 provides the catalyst of any one of Embodiments 44-57,wherein the catalyst has the structure:

wherein axial ligand L is H₂O.

Embodiment 59 provides a method of oxidation, comprising:

contacting an oxidizable starting material with the catalyst ofEmbodiment 44 and an oxidant, to provide an oxidized product.

Embodiment 60 provides the method of Embodiment 59, wherein thecontacting to provide an oxidized product is carried out undersolvent-free conditions.

Embodiment 61 provides the method of any one of Embodiments 59-60,wherein the oxidant is chosen from tert-butylhydroperoxide, hydrogenperoxide, and combinations thereof.

Embodiment 62 provides the method of any one of Embodiments 59-61,wherein the oxidizable starting material is a substituted orunsubstituted (C₁-C₅₀)hydrocarbyl alcohol.

Embodiment 63 provides the method of any one of Embodiments 59-62,wherein the oxidizable starting material is chosen from 2-pentanol,1-pentanol, and 2,4-dimethyl-3-pentanol.

Embodiment 64 provides the method of any one of Embodiments 59-63,wherein during the contacting to provide the oxidized product, thecatalyst has a turnover number of about 200 to about 10,000.

Embodiment 65 provides the method of any one of Embodiments 59-64,wherein during the contacting to provide the oxidized product, thecatalyst has a turnover number of about 300 to about 1,000.

Embodiment 66 provides the method of any one of Embodiments 59-65,wherein during the contacting to provide the oxidized product, thecatalyst has a turnover frequency of about 500 ⁻¹ to about 20,000 h⁻¹.

Embodiment 67 provides the method of any one of Embodiments 59-66,wherein during the contacting to provide the oxidized product, thecatalyst has a turnover frequency of about 1,000 h⁻¹ to about 3,000 h⁻¹.

Embodiment 68 provides a catalyst having the structure:

wherein

-   -   axial ligand L is H₂O.

Embodiment 69 provides a catalyst having the structure:

wherein

-   -   M is a metal,    -   L is a solvent molecule, and    -   at each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ are independently        chosen from —H, halide, an organic group, and a hydrophilic        group.

Embodiment 70 provides the catalyst of Embodiment 69, wherein

R¹ and R⁶ are —H, andat each occurrence, R², R³, R⁴, and R⁵ are independently chosen from —Hand a hydrophilic group.

Embodiment 71 provides the catalyst of any one of Embodiments 69-70,wherein

R¹ and R⁶ are —H, andat each occurrence, R², R³, R⁴, and R⁵ are independently chosen from —Hand —S(O)(O)OH.

Embodiment 72 provides the catalyst of any one of Embodiments 69-71,wherein R¹ and R⁶ are —H,

at each occurrence, R², R³, R⁴, and R⁵ are independently chosen from —Hand a hydrophilic group, andat one more occurrences at least one of R², R³, R⁴, and R⁵ is ahydrophilic group.

Embodiment 73 provides the catalyst of any one of Embodiments 69-72,wherein

R¹ and R⁶ are —H,at each occurrence, R², R³, R⁴, and R⁵ are independently chosen from —Hand a hydrophilic group, andat one more occurrences at least one of R², R³, R⁴, and R⁵ is a—S(O)(O)OH.

Embodiment 74 provides a method of oxidation, comprising:

contacting an oxidizable starting material with the catalyst of any oneof Embodiments 69-73 and an oxidant, to provide an oxidized product.

Embodiment 75 provides the method of Embodiment 74, wherein thecontacting to provide an oxidized product is carried out under solventfree conditions.

Embodiment 76 provides the method of any one of Embodiments 74-75,wherein the oxidizable starting material is a substituted orunsubstituted (C₁-C₅₀)hydrocarbyl alcohol.

Embodiment 77 provides the method of any one of Embodiments 74-76,wherein the oxidizable starting material is chosen from 2-pentanol,1-pentanol, and 2,4-dimethyl-3-pentanol.

Embodiment 78 provides a method of forming a catalyst, comprisingforming the catalyst of Embodiment 69-73.

Embodiment 79 provides a method of forming a derivatized catalyst,comprising adding a hydrophilic group to the catalyst of any one ofEmbodiments 69-73.

Embodiment 80 provides a method of oxidation, comprising contacting anoxidizable starting material, the derivatized catalyst of Embodiment 79,an oxidant, and water, to form an oxidized product.

Embodiment 81 provides a method of forming a derivatized catalyst,comprising sulfonating the catalyst of any one of Embodiments 69-73.

Embodiment 82 provides a catalyst having the structure:

wherein L is H₂O.

Embodiment 83 provides a catalyst having the structure:

wherein

-   -   L is water,    -   at each occurrence R², R³, R⁴, and R⁵ are independently chosen        from —H and —S(O)(O)OH, and    -   at one or more occurrences at least one of R², R³, R⁴, and R⁵ is        —S(O)(O)OH.

Embodiment 84 provides a method of oxidation, comprising:

contacting an oxidizable starting material comprising an alkene with acatalyst and an oxidant, to provide an oxidized product;wherein the catalyst is the catalyst of any one of Embodiments 44-58 or68-73.

Embodiment 85 provides the method of Embodiment 84, wherein the oxidantcomprises oxygen.

Embodiment 86 provides the method of any one of Embodiments 84-85,wherein the contacting is conducted in the presence of air to provideoxygen as the oxidant from the air.

Embodiment 87 provides the method of any one of Embodiments 84-86,wherein the contacting is performed in the absence of solvent other thanthe oxidizable starting material.

Embodiment 88 provides the method of any one of Embodiments 84-87,wherein the contacting oxidizes the alkene in the oxidizable startingmaterial to an oxidized group in the oxidized product, the oxidizedgroup comprising an epoxide, a ketone, an aldehyde, or a combinationthereof.

Embodiment 89 provides the method of Embodiment 84-88, wherein thealkene is a terminal alkene, and wherein the oxidized group is analdehyde.

Embodiment 90 provides the method of any one of Embodiments 84-89,wherein the oxidizable starting material is styrene and the oxidizedproduct is benzaldehyde, styrene oxide, oligomerization and/orpolymerization products of styrene and/or of the oxidation productsthereof, or a combination thereof.

Embodiment 91 provides the method of any one of Embodiments 84-90,wherein the oxidizable starting material is cyclohexene and the oxidizedproduct is cyclohexene oxide, 2-cyclohexene-1-ol, 2-cyclohexene-1-one,2,3-epoxy-1-cyclohexanol, 2,3-epoxycyclohexanone, or a combinationthereof.

Embodiment 92 provides the method of any one of Embodiments 84-91,wherein the contacting comprises:

contacting styrene with the catalyst and oxygen provided by air in theabsence of added solvent, to provide benzaldehyde.

Embodiment 93 provides the method of any one of Embodiments 84-92,wherein the contacting comprises:

contacting cyclohexene with the catalyst and oxygen provided by air inthe absence of added solvent, to provide cyclohexene oxide,2-cyclohexene-1-ol, 2-cyclohexene-1-one, 2,3-epoxy-1-cyclohexanol,2,3-epoxycyclohexanone, or a combination thereof.

Embodiment 94 provides the method of any one of Embodiments 84-93,wherein the catalyst is a purified catalyst that is about 95 wt % pureto about 100 wt % pure.

Embodiment 95 provides the method of any one of Embodiments 84-94,wherein the catalyst is supported (e.g., on activated charcoal oranother solid support).

Embodiment 96 provides the method of any one of Embodiments 84-94,wherein the catalyst is unsupported.

Embodiment 97 provides the catalyst or method of any one or anycombination of Embodiments 1-96 optionally configured such that allelements or options recited are available to use or select from.

What is claimed is:
 1. A method of oxidation, comprising: contacting anoxidizable starting material comprising an alkene with a catalyst and anoxidant, to provide an oxidized product; wherein the catalyst has thestructure

wherein M is a metal, axial ligand L is a solvent molecule, at eachoccurrence, R^(A) and R^(B) are independently chosen from —H, halide, anorganic group, and a hydrophilic group, or R^(A) and R^(B) together forma fused aromatic ring with the ring upon which R^(A) and R^(B) aresubstituted, R^(A) and R^(B) together having the structure:

and at each occurrence, R¹, R², R³, R⁴, R⁵, and R⁶ are eachindependently chosen from —H, halide, an organic group, and ahydrophilic group.
 2. The method of claim 1, wherein the oxidantcomprises oxygen.
 3. The method of claim 1, wherein the contacting isconducted in the presence of air to provide oxygen as the oxidant fromthe air.
 4. The method of claim 1, wherein the contacting is performedin the absence of solvent other than the oxidizable starting material.5. The method of claim 1, wherein the contacting oxidizes the alkene inthe oxidizable starting material to an oxidized group in the oxidizedproduct, the oxidized group comprising an epoxide, a ketone, analdehyde, or a combination thereof.
 6. The method of claim 5, whereinthe alkene is a terminal alkene, and wherein the oxidized group is analdehyde.
 7. The method of claim 1, wherein the oxidizable startingmaterial is styrene and the oxidized product is benzaldehyde, styreneoxide, oligomerization and/or polymerization products of styrene and/orof the oxidation products thereof, or a combination thereof.
 8. Themethod of claim 1, wherein the oxidizable starting material iscyclohexene and the oxidized product is cyclohexene oxide,2-cyclohexene-1-ol, 2-cyclohexene-1-one, 2,3-epoxy-1-cyclohexanol,2,3-epoxycyclohexanone, or a combination thereof.
 9. The method of claim1, wherein the contacting comprises: contacting styrene with thecatalyst and oxygen provided by air in the absence of added solvent, toprovide benzaldehyde.
 10. The method of claim 1, wherein the contactingcomprises: contacting cyclohexene with the catalyst and oxygen providedby air in the absence of added solvent, to provide cyclohexene oxide,2-cyclohexene-1-ol, 2-cyclohexene-1-one, 2,3-epoxy-1-cyclohexanol,2,3-epoxycyclohexanone, or a combination thereof.
 11. The method ofclaim 1, wherein the catalyst is a purified catalyst that is about 95 wt% pure to about 100 wt % pure.
 12. The method of claim 1, wherein axialligand L is chosen from CH₃CN, MeOH, and H₂O.
 13. The method of claim 1,wherein the catalyst is supported on a solid substrate.
 14. The methodof claim 1, wherein at each occurrence, the hydrophilic group is chosenfrom —C(O)OH, —O—C(O)OH, —P(O)(OH)₂, —OP(O)(OH)₂, —S(O)(O)OH,—OS(O)(O)OH, a salt thereof, a substituted or unsubstituted(C₁-C₅₀)hydrocarbyl ester thereof, and a combination thereof.
 15. Themethod of claim 1, wherein the hydrophilic group is the hydrophilicgroup is —S(O)(O)OH.
 16. The method of claim 1, wherein at one moreoccurrences at least one of R², R³, R⁴, and R⁵ is —S(O)(O)OH.
 17. Themethod of claim 1, wherein M is chosen from Co and Fe.
 18. The method ofclaim 1, wherein the catalyst has the structure:

wherein axial ligand L, is H₂O.
 19. The method of claim 1, wherein thecatalyst has the structure:

wherein M is a metal, L is a solvent molecule, and at each occurrence,R¹, R², R³, R⁴, R⁵ and R⁶ are independently chosen from —H, halide, anorganic group, and a hydrophilic group.
 20. The method of claim 19,wherein R¹ and R⁶ are —H, and at each occurrence, R², R³, R⁴, and R⁵ areindependently chosen from —H and a hydrophilic group.